1. Field of the Invention
The present invention relates to a polyamide composition and moldings therefrom. The polyamide composition of the invention has good flame retardancy and heat resistance, and exhibits good thermal stability and continuous moldability when molded in melt, and it can be molded into good moldings having excellent appearances, especially fine color tone, without giving much gas. Therefore, the polyamide composition is favorable to applications that require flame retardation, for example, to components of electric and electronic appliances such as connectors, switches, relays, printed-wiring boards, etc.; reflecting mirrors such as lamp reflectors, etc.; various components of machines; various components of decorations; films, sheets, fibers, etc.
2. Description of the Background
As having excellent properties and good melt-moldability, polyamides such as nylon 6, nylon 66, nylon 46, semiaromatic polyamides and others are heretofore much used for components of electric and electronic appliances. However, those polyamides are easily combustible resins. Therefore, in the field that requires flame retardation, for example, for components of electric and electronic appliances and others, used are polyamide compositions containing a flame retardant and a flame-retardant synergist. As the flame retardant for that purpose, generally used are brominated polymers; and as the flame-retardation synergist, used are antimony oxide compounds.
For example, in Japanese Patent Laid-Open No. 260951/1988 (U.S. Pat. No. 5,115,010), it is written that a polyamide composition as prepared by adding a halogenopolystyrene and/or a polycondensate of a halogenophenol, and sodium antimonate to a semiaromatic polyamide has good flame retardancy, good heat resistance and good mechanical properties. In Japanese Patent Laid-Open No. 320503/1993, it is written that a polyamide composition as prepared by adding a polybromostyrene and sodium antimonate to a crystalline polyamide resin having a melting point of not lower than 270.degree. C. has good heat resistance and gives good moldings having excellent surface appearances.
However, the present inventors have found that the polyamide compositions comprising a brominated polymer and sodium antimonate such as those described in the patent publications noted above could not exhibit good thermal stability and give much gas when they are molded in melt, and that their moldings have poor appearances in that they are unfavorably colored.